A Bus Factor defines the number of developers that are vital to a project.
A Code Review is a software quality assurance practice in which developers check each other’s code, usually before merging the code.
Debugging can be very annoying.
A pull request is a practice of getting feedback from other programmers and deciding to "merge" or "do not merge" the code before it is merged into the main codebase.
Continuous Integration (CI) is a practice of integrating code changes on a daily basis.
Git Flow is one of many styles of Git workflows - a branching model set for Git.
Git is one of many VCS that are there in the market but it simply is the most popular among the developers.